三江北段海子山地区铀钍地球化学异常特征及其找矿意义

摘要

Based on 1∶5 0000 stream sediment geochemical survey in Haizishan area,the content of uranium and thorium-isanalyzed,geochemical parametersare calculated,the anomaly thresholdis determined,theanomaly area of uranium and thori-um are delineated in this paper.The geochemical anomaly of uranium and thoriumisanalyzed and explained,and discussed its prospecting significance.Theresults areas follows:1 )The geochemical anomaly of uranium and thorium in Haizishan area is significant,large range,high abnormal strength,and obvious concentration centers;2 )the anomaly distribution of uranium and thorium is closely related to granite of Yanshan period.The No.I anomaly area is related to Genie granite that is located in thesouthwest of study area.The No.II anomaly area is related to Rongyicuo granite that is located in thenorthern of study are-a;3)Uranium in granite of Haizishan area is easier weathered from granite,activation,migration into the sediments than thori-um.At last,uranium is further enriched than thorium.The results provides important implications for the prospecting in gran-ite.%在海子山地区进行1∶50000水系沉积物地球化学测量基础上，分析了铀钍的含量，计算了地球化学参数，确定了异常下限，圈定了铀钍异常区，并对异常进行了分析和解释，探讨了异常在该区的找矿意义。研究发现：①海子山地区铀钍异常明显，异常范围大，强度高，浓集中心明显；②铀钍异常的分布与燕山期花岗岩体密切相关，其中I 号异常区与西南部的格聂岩体有关， II号异常区与北部的绒衣措岩体有关；③海子山地区花岗岩体中铀较钍更容易从花岗岩体中风化（活化）、迁移出来进入沉积物进一步富集，为研究区在花岗岩中找矿提供了重要的指示意义。